CWE-228 Classe Incompleto

Improper Handling of Syntactically Invalid Structure

This vulnerability occurs when software fails to properly reject or process input that doesn't follow the expected format or structure, often leading to crashes or unexpected behavior.

Definição

What is CWE-228?

This vulnerability occurs when software fails to properly reject or process input that doesn't follow the expected format or structure, often leading to crashes or unexpected behavior.
When software expects data in a specific format—like JSON, XML, protocol messages, or file structures—it must rigorously validate that incoming input matches that exact syntax. If the code assumes the input is always well-formed and doesn't implement proper error handling for malformed data, attackers can exploit this by sending deliberately invalid structures. This can trigger unhandled exceptions, cause the application to crash, or bypass security checks that rely on correct parsing. To prevent this, developers should implement strict validation at all data entry points, using well-tested parsers and libraries instead of custom logic. Always define clear error-handling routines that safely reject invalid input without exposing internal details, and design systems to fail securely—defaulting to a denied state—when encountering unexpected syntax. Regular fuzz testing with invalid inputs helps uncover these hidden parsing weaknesses before attackers do.
Impacto no mundo real

Real-world CVEs caused by CWE-228

  • CVE-2004-0270

    Anti-virus product has assert error when line length is non-numeric.

Como os atacantes a exploram

Trajeto do atacante passo a passo

  1. 1

    Identificar um caminho de código que trata input não confiável sem validação.

  2. 2

    Criar um payload que explora o comportamento inseguro — injeção, traversal, overflow ou abuso de lógica.

  3. 3

    Entregar o payload através de um pedido normal e observar a reação da aplicação.

  4. 4

    Iterar até que a resposta exponha dados, execute código do atacante ou escale privilégios.

Exemplo de código vulnerável

Vulnerable Java

This Android application has registered to handle a URL when sent an intent:

Vulnerável Java 
```
...* 
  IntentFilter filter = new IntentFilter("com.example.URLHandler.openURL");
  MyReceiver receiver = new MyReceiver();
  registerReceiver(receiver, filter);
  
   *...* 
  
  public class UrlHandlerReceiver extends BroadcastReceiver {
  ```
  		@Override
  		public void onReceive(Context context, Intent intent) {
  				if("com.example.URLHandler.openURL".equals(intent.getAction())) {
  					String URL = intent.getStringExtra("URLToOpen");
  					int length = URL.length();
```
...* 
  				}}}
Exemplo de código seguro

Secure pseudo

Seguro pseudo 
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
  const safe = validateAndEscape(input);
  return executeWithGuards(safe);
}
What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Lista de verificação de prevenção

How to prevent CWE-228

  • Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
  • Implementation Validate input at trust boundaries; use allowlists, not denylists.
  • Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
  • Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
  • Operation Monitor logs for the runtime signals listed in the next section.
Sinais de deteção

How to detect CWE-228

Automated Static Analysis High

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Correção automática do Plexicus

O Plexicus deteta automaticamente o CWE-228 e abre um PR de correção em menos de 60 segundos.

O Codex Remedium analisa cada commit, identifica esta fraqueza exata e entrega um pull request pronto para revisão com o patch. Sem tickets. Sem transferências.

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Perguntas frequentes

Frequently asked questions

O que é o CWE-228?

This vulnerability occurs when software fails to properly reject or process input that doesn't follow the expected format or structure, often leading to crashes or unexpected behavior.

Qual a gravidade do CWE-228?

A MITRE não publicou uma classificação de probabilidade de exploração para esta fraqueza. Trate-a como impacto médio até o seu modelo de ameaças provar o contrário.

Que linguagens ou plataformas são afetadas pelo CWE-228?

A MITRE não especificou as plataformas afetadas por este CWE — pode aplicar-se à maioria das stacks de aplicações.

Como posso prevenir o CWE-228?

Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.

Como é que o Plexicus deteta e corrige o CWE-228?

O motor SAST do Plexicus correlaciona a assinatura de fluxo de dados do CWE-228 em cada commit. Quando é encontrada uma correspondência, o nosso agente Codex Remedium abre um PR de correção com o código corrigido, testes e um resumo de uma linha para o revisor.

Onde posso saber mais sobre o CWE-228?

A MITRE publica a definição canónica em https://cwe.mitre.org/data/definitions/228.html. Pode também consultar a documentação da OWASP e do NIST para orientações adjacentes.

Fraquezas relacionadas

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Recursos

Further reading

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